title: Prevalence of self-reported seasonal affective disorders and the validity of the seasonal pattern assessment questionnaire in young adults Findings from a Swiss community study.
abstract: BACKGROUND
  The objective of this study was to expand the knowledge on the prevalence of self-reported Seasonal Affective Disorder (SAD) and to further study the validity of the Seasonal Pattern Assessment Questionnaire (SPAQ).
  
  
  METHODS
  A total of N=844 young adults were assessed in a Swiss community study by use of the SPAQ, a Seasonal Affective Disorders Questionnaire (SADQ), the Young Adult Self Report (YASR), the Centre for Epidemiologic Depression Scale (CES-D), and scales for measuring self-esteem, self-awareness and life events. At a second stage, a total of N=534 screen positives and controls were subjected to the Composite International Diagnostic Interview (M-CIDI) for the assessment of mental disorders. According to the SPAQ classification a group of SAD subjects and a group of subsyndromal SAD subjects (S-SAD) were defined. In addition, a third group of high-scoring depressives (HSD) subjects scoring above the 75th percentile of the CES-D was defined. Comparisons included these three groups and the rest of the sample serving as controls.
  
  
  RESULTS
  The weighted prevalence for SAD in this sample was 7.84% based on the SPAQ alone. With the addition of the SADQ, weighted prevalence rates dropped to 2.22%. Weighted subsyndromal SAD was 33.04%. Across the vast majority of scales, the SAD group was indistinguishable from the HSD group. These two groups scored highest, whereas the S-SAD group had an intermediate position and the controls had the lowest scores. SAD was best predicted by the CES-D total score.
  
  
  CONCLUSIONS
  The SPAQ as a single measure leads to an overestimation of SAD which, nevertheless, is a rather common phenomenon also in this central European population. The findings on the validity of the SPAQ are extended by showing that predominantly general aspects of depression are measured.
authors.affiliation: Aalborg Psychiatric Clinic, Aarhus University Hospital, Denmark. hc.steinhausen@kjpd.uzh.ch
authors.forename: Hans-Christoph
authors.initials: HC
authors.lastname: Steinhausen
authors.forename: Ronnie
authors.initials: R
authors.lastname: Gundelfinger
authors.forename: Christa
authors.initials: C
authors.lastname: Winkler Metzke
mesh_terms: D000293:Adolescent; D001364:Awareness; D015331:Cohort Studies; D003863:Depression / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006801:Humans; D008016:Life Change Events; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis / Q000453:epidemiology; D010555:Personality Inventory / Q000592:standards* / Q000706:statistics & numerical data; D015995:Prevalence; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D016574:Seasonal Affective Disorder / Q000175:diagnosis* / Q000453:epidemiology* / Q000523:psychology; D012649:Self Concept; D011795:Surveys and Questionnaires; D013557:Switzerland / Q000453:epidemiology; D055815:Young Adult